POU5F1 enhances the invasiveness of cancer stem-like cells in lung adenocarcinoma by upregulation of MMP-2 expression

Epsin bioactive coating reduced in-stent intimal hyperplasia by promoting early phase reendothelialization and inhibiting smooth muscle cell proliferation

In recent years, interventional surgery has become a treatment for ischemic stroke due to its low risk of injury. However, the occurrence of restenosis hinders the long-term effectiveness and safety of stent implantation. At present, drug-eluting stents mainly prevent the stenosis of drug-eluting stents by inhibiting the proliferation of smooth muscle cells (SMCs). However, these drugs cause damage to endothelial cells (ECs), prevent timely re endothelialization of blood vessels, and increase the risk of late thrombosis and late restenosis. EPS-15-interacting protein 1 (Epsin1)- EPS-15-interacting protein 2 (Epsin2)-shrna coated stents have the potential to promote early endothelialization and inhibit restenosis, which contributes to the candidate development of novel drug coated stents. We found that the expression of Epsin was elevated in the mouse carotid artery ligation model, and the intimal hyperplasia(IH) could be reduced by intervening Epsin. Epsin in cultured endothelial cells was interfered to study proliferation and migration functions, and its role in cocultured endothelial cells and smooth muscle cells was evaluated. In addition, we explored the potential therapeutic benefits of inhibiting Epsin in a porcine model using scaffolds coated with plasmids containing Epsin short hairpin RNA (shRNA). Our study showed that the expression of Epsin1 and Epsin2 was elevated in the proliferative intima of mice, and the inhibition of Epsin reduced the proliferation of neointima in mice. The inhibition of Epsin led to enhanced proliferation and migration of endothelial cells, and maintained a healthy cell membrane potential. In cocultured cells, inhibition of Epsin resulted in reduced proliferation and migration of smooth muscle cells. In a porcine carotid artery model, Epsin shRNA coated scaffolds promoted early re endothelialization and reduced IH. These results suggest that Epsin plays a crucial role in endothelial and smooth muscle cell proliferation and migration functions, and its inhibition may be a potentially effective therapeutic strategy to prevent in stent stenosis.

Up-Regulation of miR-625-5p Correlates with Suppressed Sox2, Increased Apoptosis, and Cell Cycle Arrest via The PI3K/AKT Signalling Pathway in Acute Myeloid Leukaemia

Background: Up-regulation of the microRNA-625 and abnormal expression of the Sox2 gene have been studied and seen in several tumors. Few reports have also shown the aberrant expression of miR-625 and Sox2 expression in various cancers. Several studies have also confirmed that phosphatidylinositol 3' -kinase /protein kinase B pathways regulate hematological malignancies, including Acute Myeloid Leukemia (AML). Thus, this study aimed to investigate the effects of mir-625 up-regulation on proliferation, apoptosis, and cell cycle by targeting the Sox2 gene via the downstream Akt signaling pathway and cell cycle regulators, such as p21, p27, and cyclin E in the KG-1 cell line. Materials and Methods: Cells obtained from the KG-1 cell line were cultured and transfected with plasmid DNA (miR-625) and scrambled as the control using the Lonza electroporation system. Flow cytometry was used to evaluate cell cycle, proliferation, and apoptosis. Relative gene expression was validated by qRT-PCR. All data were analyzed using graph pad prism 7.01 and REST 2009. Results: KG-1 cells transfected with the mir625-GFP construct showed decreased proliferation, increased apoptosis, and induced cell cycle arrest. Low levels of Sox2, p21, cyclin E, and up-regulation of p27 were confirmed and validated by qRT-PCR ( P < 0.05 ). Conclusion: MiR-625 can be a promising approach to aid in the treatment of AML. However, further studies are required in this field.

Stemness related lncRNAs signature for the prognosis and tumor immune microenvironment of ccRCC patients

Long non-coding RNAs (lncRNAs) and cancer stem cells (CSCs) are crucial for the growth, migration, recurrence, and medication resistance of tumors. However, the impact of lncRNAs related to stemness on the outcome and tumor immune microenvironment (TIME) in clear cell renal cell carcinoma (ccRCC) is still unclear. In this study, we aimed to predict the outcome and TIME of ccRCC by constructing a stem related lncRNAs (SRlncRNAs) signature. We firstly downloaded ccRCC patients' clinical data and RNA sequencing data from UCSC and TCGA databases, and abtained the differentially expressed lncRNAs highly correlated with stem index in ccRCC through gene expression differential analysis and Pearson correlation analysis. Then, we selected suitable SRlncRNAs for constructing a prognostic signature of ccRCC patients by LASSO Cox regression. Further, we used nomogram and Kaplan Meier curves to evaluate the SRlncRNA signature for the prognose in ccRCC. At last, we used ssGSEA and GSVA to evaluate the correlation between the SRlncRNAs signature and TIME in ccRCC. Finally, We obtained a signtaure based on six SRlncRNAs, which are correlated with TIME and can effectively predict the ccRCC patients' prognosis. The SRlncRNAs signature may be a noval prognostic indicator in ccRCC.

Unmasking the Deceptive Nature of Cancer Stem Cells: The Role of CD133 in Revealing Their Secrets

Cancer remains a leading cause of death globally, and its complexity poses a significant challenge to effective treatment. Cancer stem cells and their markers have become key players in tumor growth and progression. CD133, a marker in various cancer types, is an active research area as a potential therapeutic target. This article explores the role of CD133 in cancer treatment, beginning with an overview of cancer statistics and an explanation of cancer stem cells and their markers. The rise of CD133 is discussed, including its structure, functions, and occurrence in different cancer types. Furthermore, the article covers CD133 as a therapeutic target, focusing on gene therapy, immunotherapy, and approaches to affect CD133 expression. Nanoparticles such as gold nanoparticles and nanoliposomes are also discussed in the context of CD133-targeted therapy. In conclusion, CD133 is a promising therapeutic target for cancer treatment. As research in this area progresses, it is hoped that CD133-targeted therapies will offer new and effective treatment options for cancer patients in the future.

Exploring the function of stromal cells in cholangiocarcinoma by three-dimensional bioprinting immune microenvironment model

The tumor immune microenvironment significantly affects tumor progression, metastasis, and clinical therapy. Its basic cell components include tumor-associated endothelial cells, fibroblasts, and macrophages, all of which constitute the tumor stroma and microvascular network. However, the functions of tumor stromal cells have not yet been fully elucidated. The three-dimensional (3D) model created by 3D bioprinting is an efficient way to illustrate cellular interactions in vitro. However, 3D bioprinted model has not been used to explore the effects of stromal cells on cholangiocarcinoma cells. In this study, we fabricated 3D bioprinted models with tumor cells and stromal cells. Compared with cells cultured in two-dimensional (2D) environment, cells in 3D bioprinted models exhibited better proliferation, higher expression of tumor-related genes, and drug resistance. The existence of stromal cells promoted tumor cell activity in 3D models. Our study shows that 3D bioprinting of an immune microenvironment is an effective way to study the effects of stromal cells on cholangiocarcinoma cells.

The Tumorigenic Potential of Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) are currently evaluated for clinical applications due to their proliferation and differentiation capacities, raising the need to both assess and enhance, the safety of hPSC-based treatments. Distinct molecular features contribute to the tumorigenicity of hPSCs, manifested in the formation of teratoma tumors upon transplantation in vivo. Prolonged in vitro culturing of hPSCs can enhance selection for specific genetic aberrations, either at the chromosome or gene level. Some of these aberrations are tightly linked to human tumor pathology and increase the tumorigenic aggressiveness of the abnormal cells. In this perspective, we describe major tumor-associated risk factors entailed in hPSC-based therapy, and present precautionary and safety measures relevant for the development and application of such therapies.

Validating Cell Surface Proteases as Drug Targets for Cancer Therapy: What Do We Know, and Where Do We Go?

Cell surface proteases (also known as ectoproteases) are transmembrane and membrane-bound enzymes involved in various physiological and pathological processes. Several members, most notably dipeptidyl peptidase 4 (DPP4/CD26) and its related family member fibroblast activation protein (FAP), aminopeptidase N (APN/CD13), a disintegrin and metalloprotease 17 (ADAM17/TACE), and matrix metalloproteinases (MMPs) MMP2 and MMP9, are often overexpressed in cancers and have been associated with tumour dysfunction. With multifaceted actions, these ectoproteases have been validated as therapeutic targets for cancer. Numerous inhibitors have been developed to target these enzymes, attempting to control their enzymatic activity. Even though clinical trials with these compounds did not show the expected results in most cases, the field of ectoprotease inhibitors is growing. This review summarizes the current knowledge on this subject and highlights the recent development of more effective and selective drugs targeting ectoproteases among which small molecular weight inhibitors, peptide conjugates, prodrugs, or monoclonal antibodies (mAbs) and derivatives. These promising avenues have the potential to deliver novel therapeutic strategies in the treatment of cancers.

XPC Protein Improves Lung Adenocarcinoma Prognosis by Inhibiting Lung Cancer Cell Stemness

Objective: Xeroderma Pigmentosum Complementation Group C (XPC) is a protein involving in nucleotide excision repair (NER). XPC also plays an important role in the lung cancer occurrence with the mechanism remian unclear up to date. Studies showed that the increased stemness of lung cancer cells is related to the recurrence and metastasis of lung cancer. This study aimed to study and analyze the correlation of XPC with lung cancer stem cell biomarkers expression and the overall survival (OS) of lung adenocarcinoma patients. Methods: 140 cases of clinical lung adenocarcinoma tissue samples and 48 cases of paired paracancerous tissue samples were made into tissue microarray. Immunohistochemistry (IHC) was used to detect the expression of XPC and CD133 in cancer and paracancerous tissues. Semi-quantitative analysis and statistics were performed by Pannoramic Digital Slide Scanner. The expression of XPC and CD133 in fresh tissues was verified by Western blotting assay. siXPC was used to knock down XPC in lung cancer cell lines to study the effect of XPC on the expression of lung cancer stem cell biomarkers and the ability of cell invasion. And shXPC was used to knockdown XPC in A549 and H1650 to study the effect of XPC on the expression of lung cancer stem cell biomarkers. Results: IHC and Western blotting results showed that XPC expression significantly decreased, while CD133 expression significantly increased in cancer tissues comparing to paracancerous tissues (P _XPC < 0.0001, P _CD133 = 0.0395). The high level of XPC in cancer was associated with a better prognosis (Log-rank p = 0.0577) in lung adenocarcinoma patients. Downregulation of XPC in lung cancer cells showed increased expression of cancer stem cell biomarkers and the increased cell invasion abilities. Conclusion: It is suggested that XPC can exert the ability of anti-tumor formation, tumor invasion and metastasis inhibition, and prognostic survival improvement in lung adenocarcinoma patients by regulating the stemness of lung cancer cells.

Proteases Regulate Cancer Stem Cell Properties and Remodel Their Microenvironment

Proteolytic activity is perturbed in tumors and their microenvironment, and proteases also affect cancer stem cells (CSCs). CSCs are the therapy-resistant subpopulation of cancer cells with tumor-initiating capacity that reside in specialized tumor microenvironment niches. In this review, we briefly summarize the significance of proteases in regulating CSC activities with a focus on brain tumor glioblastoma. A plethora of proteases and their inhibitors participate in CSC invasiveness and affect intercellular interactions, enhancing CSC immune, irradiation, and chemotherapy resilience. Apart from their role in degrading the extracellular matrix enabling CSC migration in and out of their niches, we review the ability of proteases to modulate CSC properties, which prevents their elimination. When designing protease-oriented therapies, the multifaceted roles of proteases should be thoroughly investigated.

OCT4 regulated neointimal formation in injured mouse arteries by matrix metalloproteinase 2-mediated smooth muscle cells proliferation and migration

The excessive proliferation and migration of vascular smooth muscle cells (VSMCs) play vital roles in neointimal hyperplasia and vascular restenosis. In the present study, we aimed to investigate the function and mechanism of octamer-binding transcription factor 4 (OCT4, a key transcription factor for maintaining stem cells in de-differentiated state) on neointima formation in response to vascular injury. Quantitative reverse-transcription polymerase chain reaction and western blot results displayed a significant increase of OCT4 levels in injured carotid arteries. Immunohistochemistry and immunofluorescence assays confirmed that the increased OCT4 expression was primarily localized in α-SMA-positive VSMCs from neointima, and colocalized with PCNA in the nuclei of VSMCs. Adenovirus-mediated OCT4 overexpression in injured carotid arteries exacerbated intimal thickening, while OCT4 knockdown significantly inhibited intimal thickening. In-vitro experiments confirmed that the increased OCT4 expression in VMSCs could be induced by platelet-derived growth factor-BB (PDGF-BB) in a time-dependent manner. Overexpression of OCT4 greatly promoted VSMCs proliferation and migration, while OCT4 knockdown significantly retarded the PDGF-BB-induced excessive proliferation and migration of VSMCs. Bioinformatics analysis, dual-luciferase reporter assay, and chromatin immunoprecipitation assay confirmed that OCT4 could upregulate matrix metalloproteinases 2 (MMP2) expression through promoting its transcription. Moreover, knockdown of MMP2 significantly attenuated OCT4-mediated VSMCs proliferation and migration. These results indicated that OCT4 facilitated neointimal formation in response to vascular injury by MMP2-mediated VSMCs proliferation and migration, and targeting OCT4 in VSMCs might be a novel therapeutic strategy for vascular restenosis.

Diagnostic significance and carcinogenic mechanism of pan-cancer gene POU5F1 in liver hepatocellular carcinoma

BACKGROUND

The prognostic and clinicopathological significance of POU Class 5 Homeobox 1 (POU5F1) among various cancers are disputable heretofore. The diagnostic value and functional mechanism of POU5F1 in liver hepatocellular carcinoma (LIHC) have not been studied thoroughly.

METHODS

An integrative strategy of meta-analysis, bioinformatics, and wet-lab approach was used to explore the diagnostic and prognostic significance of POU5F1 in various types of tumors, especially in LIHC. Meta-analysis was utilized to investigate the impact of POU5F1 on prognosis and clinicopathological parameters in various cancers. The expression level and diagnostic value of POU5F1 were assessed by qPCR in plasma collected from LIHC patients and controls. The correlation between POU5F1 and tumor infiltrating immune cells (TIICs) in LIHC was evaluated by CIBERSORT. Gene set enrichment analysis (GSEA) was performed based on TCGA. Hub genes and related pathways were identified on the basis of co-expression genes of POU5F1.

RESULTS

Elevated POU5F1 was associated with poor OS, DFS, RFS, and DSS in various cancers. POU5F1 was confirmed as an independent risk factor for LIHC and correlated with tumor occurrence, stage, and invasion depth. The combination of POU5F1 and AFP in plasma was with high diagnostic validity (AUC = 0.902, p < .001). Specifically, the level of POU5F1 was correlated with infiltrating levels of B cells, T cells, dendritic cells, and monocytes in LIHC. GSEA indicated that POU5F1 participated in multiple cancer-related pathways and cell proliferation pathways. Moreover, CBX3, CCHCR1, and NFYC were filtered as the central hub genes of POU5F1.

CONCLUSION

Our study identified POU5F1 as a pan-cancer gene that could not only be a prognostic and diagnostic biomarker in various cancers, especially in LIHC, but functionally carcinogenic in LIHC.

Overexpression of DDR1 Promotes Migration, Invasion, Though EMT-Related Molecule Expression and COL4A1/DDR1/MMP-2 Signaling Axis

Purpose:

Discoidin domain receptor 1 (DDR1) belongs to a novel class of receptor tyrosine kinases. Previous evidence indicates that DDR1 overexpression promotes the aggressive growth of bladder cancer (BC) cells. This study aimed to investigate the molecular mechanisms by which DDR1 influences BC.

Methods:

DDR1 was transfected into human BC RT4 cells. DDR1, COL4A1, and MMP-2 expression in 30 BC tissues and paired adjacent tissues were examined by real-time polymerase chain reaction (RT-PCR) and immunohistochemistry. Transwell assays were conducted to determine cell migration and invasion. RT-PCR and western blot (WB) were also used to measure the DDR1, COL4A1, MMP-2, and EMT-related gene (ZEB1 and SLUG) expression in RT4 cells after DDR1 overexpression.

Results:

COL4A1 and MMP-2 interacted with DDR1 in the PPI network. RT-PCR and immunohistochemistry results showed that both mRNA and protein levels of DDR1 and COL4A1 were significantly increased in BC tissue, while the expression of MMP-2 was increased only at the mRNA level (P < 0.05). Overexpression of DDR1 in RT4 cells significantly promoted their migratory and invasive capabilities in vitro (P < 0.05). Moreover, overexpression of DDR1 in RT4 cells increased the mRNA and protein expression of ZEB1, SLUG, COL4A1, and MMP-2 (P < 0.01). DDR1-mediated migration and invasion of RT4 cells were reversed after COL4A1-siRNA treatment.

Conclusion:

DDR1 may be a potential therapeutic target in BC patients.

Cold-hearted: A case for cold stress in cancer risk

A negative correlation exists between environmental temperature and cancer risk based on both epidemiological and statistical analyses. Previously, cold stress was reported to be an effective cause of tumorigenesis. Several studies have demonstrated that cold temperature serves as a potential risk factor in cancer development. Most recently, a link was demonstrated between the effects of extreme cold climate on cancer incidence, pinpointing its impact on tumour suppressor genes by causing mutation. The underlying mechanism behind cold stress and its association with tumorigenesis is not well understood. Hence, this review intends to shed light on the role of associated factors, genetic and/or non-genetic, which are modulated by cold temperature, and eventually influence tumorigenic potential. While scrutinizing the effect of cold exposure on the body, the expression of certain genes, e.g. uncoupled proteins and heat-shock proteins, were elevated. Biological chemicals such as norepinephrine, thyroxine, and cholesterol were also elevated. Brown adipose tissue, which plays an essential role in thermogenesis, displayed enhanced activity upon cold exposure. Adaptive measures are utilized by the body to tolerate the cold, and in doing so, invites both epigenetic and genetic changes. Unknowingly, these adaptive strategies give rise to a lethal outcome i.e., genesis of cancer. Concisely, this review attempts to draw a link between cold stress, genetic and epigenetic changes, and tumorigenesis and aspires to ascertain the mechanism behind cold temperature-mediated cancer risk.

Cancer stem cells and their unique role in metastatic spread

Cancer stem cells (CSC) possess abilities generally associated with embryonic or adult stem cells, especially self-renewal and differentiation, but also dormancy and cellular plasticity that allow adaption to new environmental circumstances. These abilities are ideal prerequisites for the successful establishment of metastasis. This review highlights the role of CSCs in every step of the metastatic cascade from cancer cell invasion into blood vessels, survival in the blood stream, attachment and extravasation as well as colonization of the host organ and subsequent establishment of distant macrometastasis.

The Prognostic and Clinicopathologic Characteristics of OCT4 and Lung Cancer: A Meta-Analysis

Objective:

The relationship between OCT4 and clinicopathological features in lung cancer is shown to be controversial in recent publications. Therefore, we conducted this meta-analysis to quantitatively investigate the prognostic and clinicopathological characteristics of OCT4 in lung cancer.

Methods:

A comprehensive literature search of the PubMed, EMBASE, Cochrane Library, WOS, CNKI and Wanfang databases was performed to identify studies. Correlations between OCT4 expression and survival outcomes or clinicopathological features were analyzed using meta-analysis methods.

Results:

Twenty-one studies with 2523 patients were included. High OCT4 expression showed a poorer overall survival (OS) (univariate: HR= 2.00, 95% CI = (1.68, 2.39), p<0.0001; multivariate: HR= 2.43, 95% CI = (1.67, 3.55), p<0.0001) and median overall survival (MSR = 0.51, 95% CI = (0.44, 0.58), p < 0.0001), disease-free survival (DFS) (HR= 2.18, 95% CI = (1.30, 3.67), p = 0.003) and poorer disease-specific survival (DSS) (HR= 2.23, 95% CI = (1.21, 4.11), p = 0.010). Furthermore, high OCT4 expression was found to be related with lower 5 year disease-specific survival rate (OR= 0.24, 95% CI = (0.14, 0.41), p<0.0001) and 10 year overall survival rate (OR= 0.22, 95% CI = (0.12, 0.40), p=0.0001). Additionally, OCT4-high expression was also strongly associated with higher clinical TNM stage, lymph node metastasis, tumor distant metastasis, higher histopathologic grade, but not related with gender, smoking status, tumor size and histologic type of lung cancer.

Conclusion:

OCT4 over-expression in lung cancer was strongly related to poorer clinicopathological features and worse survival outcomes, which suggests that OCT4 could be a valuable prognostic marker in lung cancer.

MPC1 deficiency accelerates lung adenocarcinoma progression through the STAT3 pathway

Mitochondrial pyruvate carrier 1 (MPC1), a key factor that controls pyruvate transportation in the mitochondria, is known to be frequently dysregulated in tumor initiation and progression. However, the clinical relevance and potential molecular mechanisms of MPC1 in lung adenocarcinoma (LAC) progression remain to be illustrated. Herein, MPC1 was lowly expressed in LAC tissues and significantly associated with favorable survival of patients with LAC. Functionally, MPC1 markedly suppressed stemness, invasion, and migration in vitro and spreading growth of LAC cells in vivo. Further study revealed that MPC1 could interact with mitochondrial signal transducer and activator of transcription 3 (mito-STAT3), disrupting the distribution of STAT3 and reducing cytoplasmic signal transducer and activator of transcription 3 (cyto-STAT3) as well as its phosphorylation, while the activation of cyto-STAT3 by IL-6 reversed the attenuated malignant progression in MPC1-overexpression LAC cells. Collectively, we reveal that MPC1/STAT3 axis plays an important role in the progression of LAC, and our work may promote the development of new therapeutic strategies for LAC.

SOX5 interacts with YAP1 to drive malignant potential of non-small cell lung cancer cells

The dysregulation of transcription factors plays a vital role in tumor initiation and progression. Sex determining region Y-box 5 (SOX5) encodes a member of the SRY-related HMG-box family of transcription factors involved in the determination of the cell fate and the regulation of embryonic development. However, its functional roles in non-small cell lung cancer (NSCLC) remain unclear. Herein, we report that SOX5 sustains stem-like traits and enhances the malignant phenotype of NSCLC cells. We determine that SOX5 is preferentially expressed by cancer stem-like cells (CSLCs) of human NSCLC. In vitro gain- and loss-of-function studies demonstrate that SOX5 promotes self-renewal, invasion and migration in NSCLC cells. Importantly, knockdown of SOX5 potently inhibits tumor growth in a xenograft mouse model. Mechanistically, YAP1 can act as an interacting protein of SOX5 to drive the malignant potential of NSCLC cells. Silencing of YAP1 attenuates the malignant processes in NSCLC cells, which is consistent with the function of SOX5 loss. SOX5 overexpression reverses the attenuated malignant progression in YAP1 knockdown cancer cells. Taken together, these findings identify that SOX5 acts as an oncogenic factor by interacting with YAP1 in NSCLC cells and may be a potential therapeutic target for NSCLC patients.

Bowhead: Bayesian modelling of cell velocity during concerted cell migration

Cell migration is a central biological process that requires fine coordination of molecular events in time and space. A deregulation of the migratory phenotype is also associated with pathological conditions including cancer where cell motility has a causal role in tumor spreading and metastasis formation. Thus cell migration is of critical and strategic importance across the complex disease spectrum as well as for the basic understanding of cell phenotype. Experimental studies of the migration of cells in monolayers are often conducted with 'wound healing' assays. Analysis of these assays has traditionally relied on how the wound area changes over time. However this method does not take into account the shape of the wound. Given the many options for creating a wound healing assay and the fact that wound shape invariably changes as cells migrate this is a significant flaw. Here we present a novel software package for analyzing concerted cell velocity in wound healing assays. Our method encompasses a wound detection algorithm based on cell confluency thresholding and employs a Bayesian approach in order to estimate concerted cell velocity with an associated likelihood. We have applied this method to study the effect of siRNA knockdown on the migration of a breast cancer cell line and demonstrate that cell velocity can track wound healing independently of wound shape and provides a more robust quantification with significantly higher signal to noise ratios than conventional analyses of wound area. The software presented here will enable other researchers in any field of cell biology to quantitatively analyze and track live cell migratory processes and is therefore expected to have a significant impact on the study of cell migration, including cancer relevant processes. Installation instructions, documentation and source code can be found at http://bowhead.lindinglab.science licensed under GPLv3.

The expression of the embryonic gene Cripto-1 is regulated by OCT4 in human embryonal carcinoma NCCIT cells

Cripto-1 and OCT4, expressed in stem cells and cancers, play important roles in tumorigenesis. Here, we demonstrate that Cripto-1 expression is regulated by OCT4 in human embryonic carcinoma NCCIT cells. The endogenous expression of Cripto-1 and OCT4 is significantly reduced during differentiation. Cripto-1 expression is increased by OCT4 overexpression, but decreased by shRNA-mediated OCT4 knockdown. OCT4 overexpression significantly activates Cripto-1 transcriptional activity. A 5'-upstream minimal promoter sequence in the gene-encoding Cripto-1 is significantly activated by OCT4 overexpression. Mutation of the putative OCT4-binding site abolishes OCT4-mediated activation of the Cripto-1 promoter. The OCT4 transactivation domains mediate transcriptional activity of the Cripto-1 minimal promoter through direct interaction. Taken together, OCT4 plays an important role as a transcriptional activator of Cripto-1 expression in NCCIT cells.

Cancer stem cell heterogeneity: origin and new perspectives on CSC targeting

Most of the cancers are still incurable human diseases. According to recent findings, especially targeting cancer stem cells (CSCs) is the most promising therapeutic strategy. CSCs take charge of a cancer hierarchy, harboring stem cell-like properties involving self-renewal and aberrant differentiation potential. Most of all, the presence of CSCs is closely associated with tumorigenesis and therapeutic resistance. Despite the numerous efforts to target CSCs, current anti-cancer therapies are still impeded by CSC-derived cancer malignancies; increased metastases, tumor recurrence, and even acquired resistance against the anti-CSC therapies developed in experimental models. One of the most forceful underlying reasons is a “cancer heterogeneity” due to “CSC plasticity” A comprehensive understanding of CSC-derived heterogeneity will provide novel insights into the establishment of efficient targeting strategies to eliminate CSCs. Here, we introduce findings on mechanisms of CSC reprogramming and CSC plasticity, which give rise to phenotypically varied CSCs. Also, we suggest concepts to improve CSC-targeted therapy in order to overcome therapeutic resistance caused by CSC plasticity and heterogeneity.

Low-dose oral cadmium increases airway reactivity and lung neuronal gene expression in mice

Inhalation of cadmium (Cd) is associated with lung diseases, but less is known concerning pulmonary effects of Cd found in the diet. Cd has a decades-long half-life in humans and significant bioaccumulation occurs with chronic dietary intake. We exposed mice to low-dose CdCl2 (10 mg/L in drinking water) for 20 weeks, which increased lung Cd to a level similar to that of nonoccupationally exposed adult humans. Cd-treated mice had increased airway hyperresponsiveness to methacholine challenge, and gene expression array showed that Cd altered the abundance of 443 mRNA transcripts in mouse lung. In contrast to higher doses, low-dose Cd did not elicit increased metallothionein transcripts in lung. To identify pathways most affected by Cd, gene set enrichment of transcripts was analyzed. Results showed that major inducible targets of low-dose Cd were neuronal receptors represented by enriched olfactory, glutamatergic, cholinergic, and serotonergic gene sets. Olfactory receptors regulate chemosensory function and airway hypersensitivity, and these gene sets were the most enriched. Targeted metabolomics analysis showed that Cd treatment also increased metabolites in pathways of glutamatergic (glutamate), serotonergic (tryptophan), cholinergic (choline), and catecholaminergic (tyrosine) receptors in the lung tissue. Protein abundance measurements showed that the glutamate receptor GRIN2A was increased in mouse lung tissue. Together, these results show that in mice, oral low-dose Cd increased lung Cd to levels comparable to humans, increased airway hyperresponsiveness and disrupted neuronal pathways regulating bronchial tone. Therefore, dietary Cd may promote or worsen airway hyperresponsiveness in multiple lung diseases including asthma.

The emerging roles of Oct4 in tumor-initiating cells

Octamer-binding transcription factor 4 (Oct4), a homeodomain transcription factor, is well established as a master factor controlling the self-renewal and pluripotency of pluripotent stem cells. Also, a large body of research has documented the detection of Oct4 in tumor cells and tissues and has indicated its enrichment in a subpopulation of undifferentiated tumor-initiating cells (TICs) that critically account for tumor initiation, metastasis, and resistance to anticancer therapies. There is circumstantial evidence for low-level expression of Oct4 in cancer cells and TICs, and the participation of Oct4 in various TIC functions such as its self-renewal and survival, epithelial-mesenchymal transition (EMT) and metastasis, and drug resistance development is implicated from considerable Oct4 knockdown and overexpression-based studies. In a few studies, efforts have been made to identify Oct4 target genes in TICs of different sources. Based on such information, Oct4 in TICs appears to act via mechanisms quite distinct from those in pluripotent stem cells, and a main challenge for future studies is to unravel the molecular mechanisms of action of Oct4, particularly to address the question on how such low levels of Oct4 may exert its functions in TICs. Acquiring cells from their native microenvironment that are of high enough quantity and purity is the key to reliably analyze Oct4 functions and its target genes in TICs, and the information gained may greatly facilitate targeting and eradicating those cells.

Genome-wide microarray expression and genomic alterations by array-CGH analysis in neuroblastoma stem-like cells

Neuroblastoma has a very diverse clinical behaviour: from spontaneous regression to a very aggressive malignant progression and resistance to chemotherapy. This heterogeneous clinical behaviour might be due to the existence of Cancer Stem Cells (CSC), a subpopulation within the tumor with stem-like cell properties: a significant proliferation capacity, a unique self-renewal capacity, and therefore, a higher ability to form new tumors. We enriched the CSC-like cell population content of two commercial neuroblastoma cell lines by the use of conditioned cell culture media for neurospheres, and compared genomic gains and losses and genome expression by array-CGH and microarray analysis, respectively (in CSC-like versus standard tumor cells culture). Despite the array-CGH did not show significant differences between standard and CSC-like in both analyzed cell lines, the microarray expression analysis highlighted some of the most relevant biological processes and molecular functions that might be responsible for the CSC-like phenotype. Some signalling pathways detected seem to be involved in self-renewal of normal tissues (Wnt, Notch, Hh and TGF-β) and contribute to CSC phenotype. We focused on the aberrant activation of TGF-β and Hh signalling pathways, confirming the inhibition of repressors of TGF-β pathway, as SMAD6 and SMAD7 by RT-qPCR. The analysis of the Sonic Hedgehog pathway showed overexpression of PTCH1, GLI1 and SMO. We found overexpression of CD133 and CD15 in SIMA neurospheres, confirming that this cell line was particularly enriched in stem-like cells. This work shows a cross-talk among different pathways in neuroblastoma and its importance in CSC-like cells.